The hitherto known processes for preparation of compound 3 are:
(i) Oxidation of compound having formula 2 using catalytic quantity of Osmium tetroxide in the presence of N-methylmorpholine-N-oxide (Nobuo Ikekawa etal. Chem. Pharm. Bull. 1982, 30 4181-4185). PA1 (ii) Oxidation of compound having formula 2 with catalytic amount of Osmium tetroxide in the presence of N-methylmorpholine-N-oxide (Kenji Mori etal. Tetrahederon 1982, 38, 2099-2109). PA1 (iii) Oxidation of compound having formula 2 using equivalent quantity of Osmium tetroxide (C. W. Shoppe etal. J. Chem. Soc. 1957, 3100-3107).
The main drawback of all the above methods is the use of costly and highly toxic Osmium tetroxide as a reagent for the oxidation of compound having formula 2. Cis-Dihydroxylation of of said compound having formula 2 with tetradecyltrimethylammonium permanganate (TDTAP), a permanganate derived oxidizing agent, has not been reported so far. The reaction of present invention is fast, clean and can be carried out under simple condition. The reagent TDTAP is a violet crystalline solid, soluble in most of the organic solvents and easy to handle (B. G. Hazra etal. J.Chem.Soc. Perkin Trans.I 1994 1667-1669). The great advantage of the reagent TDTAP is that, it is cheap, non-toxic, selective and can be prepared very easily.